HIGH EFFICIENCY
LOW NOX
Model : Tudor NHREX
Installation & Operating
instructions
Code : L375 01-2021
Page 2
Thank you for choosing our high efficiency, low Nox hot water heater to
ensure your domestic hot water production.
Please retain the device’s operating instructions in a
safe place for future reference.
PRODUCT CONFORMING TO EU DIRECTIVE 2012/19/EU
The crossed-out wheeled bin symbol on the appliance indicates that the
end-of-life product, to be treated separately from domestic waste, must
be returned to a waste sorting centre for electrical and electronic
equipment or returned to the dealer, on the day of purchase of a new
equivalent device.
The user must ensure that the device at the end of its life is disposed of in
an appropriate collection centre.
Selective sorting, which allows the recycling of the appliance at the end of
its life cycle, the treatment of it and the environmentally friendly disposal,
helps to avoid possible negative effects on the environment, health and
recycling of the materials that make up the product.
For more information on existing waste collection centers, contact the
local waste collection service or the store where you purchased your
appliance.
Page 3
1. RECOMMENDATIONS
a. General Recommendations
1. This manual forms an integral part of the appliance. It is to be kept safe and
accessible for consultation if necessary and must accompany the appliance in case
of transfer to another owner or user and / or transfer to another installation.
2. Carefully read the instructions and understand the advice provided. This will help ensure
the safe installation, use and maintenance of the appliance.
Failure to do so may invalidate the warranty.
3. Installation, maintenance and other work must be carried out by a competent
person in accordance with the relevant regulations and the manufacturer's
instructions.
4. This appliance is designed to produce hot water for domestic use. It should be
connected to the distribution mains supply for domestic hot water in accordance with
the performance levels of the appliance.
5. This appliance must only be used for it’s intended purpose. The manufacturer can
under no circumstances be held liable for damages resulting from improper,
incorrect or unreasonable use or from non-observance of the instructions contained
in this manual.
6. The manufacturer shall not be liable for damage to persons, animals or property
caused by improper installation.
7. Ensure that all packing materials are safely disposed of (staples, plastic bags,
expanded polystyrene, etc.), as they represent a sources of danger, especially for
children.
8. Do not touch the appliance if you have bare feet or with wet parts of the body.
9. In the event of faults and/or malfunctions, switch the appliance off and shut off the
gas valve. Do not attempt to perform any repairs yourself but contact an authorised
service technician.
10. For repairs, contact an authorised service technician and specify the use of only
original spare parts where possible. Failure to comply with the above may
compromise safety and disclaim all liability of the manufacturer.
11. The hot water temperature is controlled by thermostat which also serves as a safety
device (requiring manual reset) to prevent dangerous water temperatures. To avoid
any risk of scalding, do not exceed a maximum temperature of 50 °C at the tap
discharge via suitable mixers. To avoid the risk of legionella issues, the control
thermostat must be set to at least 60 °C.
12. Ensure that the electrical connection is as indicated in the relevant section-10
13. No flammable objects should be stored in the vicinity of the appliance.
Page 4
14. If the appliance is out of service for more than one month, close the hydraulic
circuits, connected to the water heater and drain the appliance. If the appliance is
left unused in winter for a long period in an unheated space, it is advisable to
drain it completely to avoid any risk of freezing. The manufacturer shall not be liable
for damage caused by freezing or leaking water from the installation.
15. The appliance must not be installed in damp areas ( RH ≤ 80%) and must be
protected against splashing water to avoid damage to electrical and thermal
components.
16. Do not store any type of object against the appliance.
17. For reliable and safe performance and warranty recognition, carefully follow the
information in this manual and use only the spare parts supplied by the
Manufacturer.
18. This appliance should not be operated by children and they must be attended at all
times.
b. Installer Recommendations
The appliance and its safety valve (supplied separately) must be installed in a frost-
free and properly ventilated room.
It is essential that the discharge of the safety valve is connected to a tundish,
suitably connected to a drain. Specific attention to system integrity should be made
if the water heater is installed above inhabited premises ( eg.- elderly persons care
home)
To allow maintenance operations, it is imperative to provide appropriate clearances
as detailed in figure 3.
2. REGULATIONS
Gas or liquefied petroleum equipment installations must be carried out in
accordance with regulations.
This appliance may operate with a non-sealed combustion circuit of the type B11BS
Categories : II2H3P G20-20mbar - G31-37mbar
NATURE OF
GAS
COMMON DESIGNATION
NATURAL GAS PROPANE
REFERENCE GROUP H - G20
34.02MJ/m
3
G31
46.34 MJ/m3
Net calorific value (15° / 1013 mbar)
NORMAL SUPPLY PRESSURE 20 37
Page 5
a. European Directives and Standards
Directive 90/396/CEE as amended by 2009/142/CE Gas appliances ;
Directives 2009/125/EC (ErP) & 2010/30EU (Energy Labelling)
Directive DESP 97/23/CE Pressure equipment ;
BS EN 89 (2000) Devices for the production of hot water by storage for sanitary uses
using gaseous fuels ;
+ BS EN 89/ A3 (2006)
+ BS EN 89/ A4 (2007)
CEN/TR 1749 (2013) European scheme for the classification of gas appliances
according to the method of evacuation of the combustion products (types)
b. Installation Requirements
It is the Law that all gas appliances are installed by competent persons (Gas Safe
Registered), in accordance with the Gas Safety (Installation and Use)
Regulations 1998 (as amended). Health & Safety requirements must be taken into
account when installing any equipment. Failure to comply with the above may lead to
prosecution. It is in your own interest and that of safety, to ensure the Law is complied
with.
The installation of the appliance MUST be carried out by competent personnel and
comply with the I.E.E. Wiring Regulations, National & Local Building Regulations,
Water Bye-laws, Bye-Laws of the Local Water Undertaking, Fire Authority
Requirements any relevant requirements of the Local Authority, and Health and
Safety Executive.
Statutory Instruments
Water Supply (Water Quality England & Wales) Regulations 2016 - as amended
The Public Water Supplies (Scotland) Regulations 2014 - as amended
The Water Supply (Water Fittings) Regulation (Northern Ireland) 2009 - as amended
For gas fired equipment the installer should also refer to relevant IGEM Publications:
IGE/UP/1 Soundness testing and purging of industrial and commercial gas
installations.
IGE/UP/1A Soundness testing and direct purging of small low pressure industrial and
commercial natural gas installations.
IGE/UP/2 Gas installation pipe work, boosters and compressors on industrial and
commercial premises.
IGE/UP/10 Installation of gas appliances in industrial and commercial premises.
Detailed recommendations are contained in the following British Standard Codes of
Practice:
BS 5440 Flueing and ventilation for gas appliances of rated input not exceeding 70kW
net
Page 6
BS 6644 Specification for the installation and maintenance of gas-fired hot water
boilers of rated inputs between 70 kW (net) and 1.8 MW (net).
BS 6880 Part 1, 2 & 3 Code of Practice for low temperature hot water heating
systems of output greater than 45kW.
BS 7074 Part 1: Application, selection and installation of expansion vessels and
ancillary equipment for sealed water systems.
Part 2: Code of Practice for low and medium temperature hot water heating systems.
BS 7671 Requirements for electrical installations. IET Wiring Regulations.
BS 8550 Guide for the auditing of water quality sampling
BS 8558 Guide to the design, installation, and maintenance of services supplying
water for domestic use within buildings. Note: this document is complimentary to BS
EN 806
BS 14743 Water conditioning equipment inside buildings. Softeners. Requirements
for performance, safety and testing
BS EN ISO 4126-1 Safety devices for protection against excessive pressure. Safety
valves.
BS EN 806 Specification for installations inside buildings conveying water for human
consumption
Note: - BS6700 - The Design, Installation, Testing and Maintenance of Services
supplying water for domestic use within buildings; is still referred to. However this
document has been superseded by BS EN 806
BS EN 1717 Protection against pollution of potable water in water installations and
general requirements of devices to prevent pollution by back-flow
Electrical Standards:- BS 3456 Part 201, EN 60335 Part 1
CP 342-2 Code of practice for centralised hot water supply. Buildings other than
individual dwellings.
The Health and Safety Commission (HSC) approved code of practice and
guidance document L8 - HSG274: Legionnaires disease. Technical Guidance.
Note: - due to the scope of this document, all non-domestic premises must
implement some form of water treatment.
CIBSE Publications
CIBSE Guide G Public Health Engineering
CIBSE TM13: Minimising the risk of Legionnaires’ disease.
CIBSE Guide H Building Control Systems.
CIBSE Guide Energy Efficiency in Buildings.
CIBSE Commissioning Code B: 2002.
Page 7
Department of Health
Health Technical Memorandum (HTM) 04-01: The control of Legionella,
hygiene, ‘safe’ hot water, cold water and drinking water systems.
Part A Design, installation and testing.
Part B Operational Management Department of Health (DH). Addendum
Pseudonomas aeruginosa - advice for augmented care units.
HTM 04-04 The Control of Legionella in Health Care Premises- Code of
Practice: 2006
General Requirements
All connections to the local water main shall comply with Water Supply
(Water Fittings) Regulations 1999 (as amended). Compliance with the
Regulations can be demonstrated by certification from notified body
organisations such as WRAS or KIWA.
Unvented Systems
Building Regulations - use of unvented hot water storage systems with
volumes exceeding 15 litres. G3 (England & Wales), P3 (Scotland) & P2
(Northern Ireland)
The unvented system components allows the storage vessel to be fed directly
from the mains cold water supply, or from a booster pump set, without the
need for feed and expansion tanks. The unvented system components should
be approved and comply with the Water Supply (Water Fittings) Regulations
1999 (as amended), including a suitably sized temperature or temperature
and pressure (T&P) relief valve, which locates directly into the top portion of
the storage vessel.
3. WARNINGS
Notice regarding the development and publication of this manual:
➢ It contains the most recent descriptions and characteristics of the
product.
➢ The contents of this manuals are subject to change without notice :
We reserve the right to make changes, without notice, to the features and
elements contained herein. We may not be held liable for any prejudice (including
consequential damages) caused by reliance on the material presented, including,
but not limited to, typographical errors and other publication errors.
4. CONDITIONS FOR APPLICATION OF
THE MANUFACTURER’S WARRANTY
Standard and current terms of warranty are detailed on our web site www.elco.co.uk
Page 8
5. GENERAL INFORMATION
DHW high efficiency gas low NOx hot water heater. With a very simple and flexible
operation, you can always dispose of hot water at the desired temperature and the
desired flow (within the limits of the capacity of the appliance) while respecting the
(regulatory) thermal and environmental issues.
a. ERP CLASSIFICATION
Models
NHREX
18
NHREX
26
NHREX
36
NHREX
60
Energy efficiency class
B B B B
Load Profile
XL 2XL 2XL 2XL
Water Heating Energy Efficiency
nwh % 67 62 69 64
Daily Electricity Consumption
Qelec
kWh
-
0.12
0.13
0.11
Daily Fuel Consumption
kWh 31.47 39.48 35.11 38.01
Emissions of Nitrogen Oxides
mg/kWh 33 28 34 19
Annual Electricity Consumption
kWh 13 27 28 25
Annual Fuel Consumption AFC
GJ 22.6 31.2 27.8 30
Mixed water at 40°continuous
(Cold water 10°)
L
266
378
396
480
Acoustic Power
dB 49 49.2 49.8 50.8
b. Characteristics
Legend :
1. Draught diverter
2. Insulation
3. Overheat thermostat
4. Protech electronic
anode
5. Temperature control
thermostat
6. Enamelled tank
9. Condensate tray / drain
10. Gas valve
11. Main burner tubes
14. Flue tubes
15. Flue tube baffles
16. Hot water outlet G1”
17. Cold water inlet G1”
16
17
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Figure1 - general layout Plan view
General technical characteristics (see. Fig.-1a & 1b above):
➢ Enameled tank (Sanitary conformity according to standard BS EN 89)
allowing operation with a working temperature up to 95°C ;
➢ Durable padded vinyl jacket over dense thermal insulation material ;
➢ Draught diverter fitted with flue gas spillage device for connection to an
atmospheric chimney system B
11BS
;
➢ Model NHREX 18 fitted with thermoelectric, permanent pilot flame failure
system ;
➢ Models NHREX 26, 36 & 60 fitted with electronic full sequence intermittent
pilot ignition control
➢ Gas type G20/G31 ;
➢ Factory calibrated Model (Category by country) ;
➢ Low NOx Gas burner ;
➢ Integral Protech electronic anode protection system;
➢ Device certified to the European standard for gas storage water heaters, for
sanitary use (BS EN 89).
It is imperative to read this documentation before commissioning. At your
request, our Post sale department can organise a commissioning visit
(optional).
6. TECHNICAL CHARACTERISTICS
a. CE marking
We hereby certify that the DHW gas fired high efficiency low Nox storage water
heaters are in conformity with the requirements of Directive: EU 2016/426
b. Type
This appliance is certified for connection to an atmospheric chimney system B
11BS
in
accordance with CEN/TR1749 and is fitted with a flue spillage safety thermostat
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c. Technical Data
Technical Specifications Unit
NHREX 18
NHREX 26
NHREX 36
NHREX 60
DHW Capacity:
Litres 180 250 250 320
Heat Output:
kW 18.7 27.8
36.1
51.5
Heat Input:
kW 22.0
32.0
42.0 60.0
Gross Thermal Efficiency:
% 85 86.9 86 85.8
DHW Recovery Time (
△
T = 50 °C):
min 34 31 23 22
Hot Water Production (
△
T = 50 °C):
l/h 322 479 621 887
l/min 5.36 7.98 10.35 14.8
Hot Water Production (
△
T = 55 °C):
l/h 293 435 564 806
l/min 4.88 7.26 9.4 13.4
Gas Consumption (G20-20 mbar)*: m
3
/h 2.3 3.4 4.5 6.3
Gas Consumption (G31 – 37 mbar)*: kg/h 1.3 1.71 1.8 2.3
Flue gas temperature (maximum): °C 120 130 135 130
Flue gas flow rate:
17 22 24
g/s
11
Flue connection internal diameter: mm 126 140 168 180
Total Power Consumption
230 V ~ 50 Hz (IP 20) :
W 5 20 20 20
Minimum / Maximum Working
Pressure :
Bar 1/7 1/7 1/7 1/7
Maximum Working Temperature: °C 80 80 80 80
Dimensions (B x Ø x A):
mm
1210 x
790 x
1468
1530 x
790 x
1791
1530 x
790 x
1840
1890 x
790 x
2200
Packaged Dimensions (wooden box)
(H*W*D):
mm
1286 x
912 x
1008
1583 x
912 x
1008
1583 x
912 x
1008
1961 x
912 x
1008
Empty Weight: Kg
165 196 196
245
Full Weight: Kg
350 450 450 570
NOx Emissions:
mg/kWh
33 28 34 19
* Gas Consumption @ 1013.25 mbar, 15°C
Page 11
d. Minimum dimensions and clearances
Figure 2 - dimensions
Legend :
16. Hot water outlet G1”
17. Cold water inlet G1”
18. Flue spillage sensor (DAT)
19. Control panel
20. Instruction label
21. Inspection port
22. Nameplate
23. Warning label
26. Combustion chamber
cover
27. Gas inlet pipe
Note: Clearance above should be sufficient
to allow disconnection of flue system
and removal of flue baffles.
Figure 3 - Minimum clearances
NHREX 18 26 36 60
A 750 750 750 750
Top 500 500 500 500
B 150 150 150 150
NHREX
18 26 36 60
A 1468 1791 1840 2200
B 1210 1530 1530 1890
C 1245 1560 1560 1920
B
B
B
A
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e. Packaging / Storage / Transport / Unpacking
Each unit, after factory checks and tests, is packaged in a wooden box and stored in a
warehouse with optimum conditions for delivery.
This appliance must be stored in a covered, frost-free room with high and low ventilation.
When it is transported, it must be fixed vertically and strongly in its original packaging until
the place of installation.
In order to unpack the device for its installation on the site, here is the procedure to
follow :
Dismantling the wooden box:
- Uncouple the cap : 1
- Remove the posts : 2 et 3
- Remove the 4 screws : 4
- Remove the posts : 5 et 6
Warning!
After unpacking the unit, make sure that it is
completely intact.
Packaging elements must be sorted and collected
according to their nature for environmental
protection.
Page 13
7. HYDRAULIC CONNECTION & GAS
a. Hydraulic Connection
Revert to Figures 7.1 - 7.4 to visualise the schematics of some of the main features to link the
hydraulic connections. The correct installation of the tank is the responsibility of the
installer. Ensure that each unit and the associated pipe work are suitably earthed.
Legend :
1. Cold water mains
supply
2. Isolating valve
3. Strainer
4. Pressure reducing
valve
5. Expansion vessel
6. Non return valve
7. Pressure relief valve
8. Drain valve
9. NHREX water heater
10. Re-circulating pump
11. Hot water outlets
12. Temperature &
Pressure relief valve
13. De-Stratification pump
14. Buffer vessel loading
pump
15. DHW Storage
Cylinder
Figure 7.1 - NHREX Open vented system
Figure 7.2 - NHREX Unvented system - optional cold water boosted supply
6
Page 14
Figure 7.3 - Two NHREX in parallel unvented
Figure 7.4- NHREX with buffer vessel unvented
Page 15
Figures -7.3 & 7.4 represents the general idea on how to link 2 appliances (in parallel) in
order to double the capacity of production. Also the schematic for 2 appliances (also in
parallel) with a buffer tank allowing an increased capacity of production and ensuring a
better quality of service and the availability of the DHW.
b. Tips & Recommendations
☞ The Gas entry is via the
1/2
” for NHREX18 &
3/4
” for other models on the
bottom left of the tank:
➢ Ensure that a filter and isolating valve are accessible close to the appliance.
➢ The gas supply needs to have a union and valve close to the appliance.
➢ The gas supply must be in accordance with BS6644 and purged in accordance
with IGE/UP1
NOTE: The burner is preset to the correct flow
VERIFY THE NATURE OF DISTRIBUTED GAS BEFORE ADAPTATION OF THE
APPLIANCE
☞
The cold water inlet situated on top of the tank is a 1’’ connection
Open vented systems - refer BS EN 806 & BS 6700
➢ Ensure that the feed and expansion tank is sized to provide sufficient cold water
storage and accommodate system expansion without the risk of overflowing.
➢ Ensure that the static head created by the feed and expansion tank does not
exceed the maximum working pressure and that it provides sufficient head
pressure so that flow can be maintained at all outlets likely to be operating
concurrently. Minimum cold feed pipe size 1” (28mm)
➢ Ensure that the open vent pipe is adequately sized (minimum 11/4” - 32mm)
connecting the domestic hot water flow to the feed and expansion tank
➢ The fitting of a 3/4” (20mm) safety pressure relief valve to the tank flow is
recommended. No isolating valves should be fitted between the water heater
and the connection points for the open vent and relief valve
Unvented systems - refer BS EN 806 & BS 6700
➢ Install a stop valve on the cold water supply. The installation of the filter is
strongly recommended in order to eliminate any solid particulates or debris.
➢ Ensure that the setting of the pressure reducing valve does not exceed the
maximum working pressure of the water heater.
➢ Install a cold water inlet valve group (option supplied by Elco) incorporating non
return valve, pressure relief valve and pressure reducing valve
➢ Install a suitably sized expansion vessel acknowledging the system volume
(option supplied by Elco) in accordance with BS EN 7074
➢ The fitting of the T&P valve must be in accordance with Building Regulation G3.
(option supplied by Elco)
Page 16
☞ The hot water outlet situated
on top of
the tank is a 1’’ connection
Add an automatic air vent (AAV) on the hot water outlet and as close as possible
to the tank.
Do not increase the diameter of the hot water outlet pipe, as larger diameter pipes
increases heat losses.
It is strongly recommended that a thermostatic mixer/valve is installed close to
the appliance in order to avoid any risk of scalding.
The appliance drain pipe should incorporate a 1’’ valve. The drain water needs to
be visible either through a tundish or directly to drain.
Refer to BS 8558 for guidance on system design and materials. Pipe work
connected to the appliance should be easily assembled and disassembled.
Ensure that all pipe work is suitably earthed, as close as possible to the
appliance.
Check that the inlet water pressure does not exceed 5 bar. For pressure above
this limit, install a pressure reducing valve.
The condensate discharge must comply with the Building Regulations and Water
Bye-laws. Appliance discharge must not be blocked or modified.
c. Principle of Operation (see Figure -1)
The appliance is equipped with a low Nox burner. The gas passes though the injector
into the burner. The gas valve guarantees the gas flow through the injector by the
setting pressure. The gas flow through the injector entrains secondary air into the
burner tube.
Combusted gases pass from the burner into the combustion chamber and through the
heat exchanger immersed in the stored water. The flue gases pass through the heat
exchanger tubes loosing temperature as they rise through the flue way baffles into the
draught diverter and flue system.
Note: During initial cold firing or sustained high demand hot water draw off, the flue
gases may condense in the flue tubes and drip into the condense tray. The condensate
is discharged to drain from the condense tray.
The thermostat sensor monitors the water temperature in the tank. As soon as the
temperature drops to the set-point value, the controller starts the ignition cycle, and the
burner starts. Once the flame is detected, the burner ignites and the water temperature
rises. Once the correct temperature is reached, the burner switches off. If the overheat
thermostat sensor detects too high a temperature, the burner switches off and the
controls require manual reset.
8. QUALITY OF WATER
The system is intended for the storage and the production of hot water (DHW).
Under no circumstances should this equipment be fired before the cold water supply
to the equipment has been checked and treated, where required. All installations of
hot and cold water supplies shall be thoroughly flushed and cleaned
Page 17
before being filled and used. If an installation is not flushed and/or if the water is not
of the right quality, it may invalidate the manufacturer’s warranty.
Refer to ICOM document Water Quality Consideration of Domestic Hot Water
Systems for Commercial Applications.
The water must comply with the regulations for drinking water for human consumption.
Note - If the water specifications differ from the specifications in the table, the tank
protection cannot be guaranteed.
9. FLUE SYSTEMS & VENTILATION
a.
Atmospheric flues B
11BS
in accordance with CEN TR 1749
The draught diverter supplied separately with the appliance must be installed
carefully following the instructions supplied in the carton with the specific draught
diverter. The flue spillage detection safety device must also be correctly installed
following the instructions supplied with the draught diverter.
Flue spillage detection safety device (DAT) - is a thermal device that shuts down
the pilot burner when incorrect flue gas flow is detected in the draught diverter.
It is a resettable thermal device placed in series with the flame safety circuit of the
thermocouple (NHREX 18) or of the electronic board (NHREX 26-60) in addition to
the overheat safety thermostat.
The DAT thermostat causes the burner to stop completely if faults occur due to
improper draft in the flue.
To restart the device, you must:
o
Isolate the electrical supply before accessing the reset button in the control
panel
o
Reset the thermostat (DAT) (ref 6 figure 11.2) located inside the control
panel
o
IMPORTANT - This device must never be taken out of service. Any
intervention on this device is strongly discouraged as serious risks to
personal safety may occur.
Should the device operate frequently, call the installer or after-sales service
approved by the manufacturer.
The flue pipe and fittings used must be of appropriate corrosion resistant material.
The diameter of the flue used must not be smaller than the flue connection on the
Page 18
appliance draught diverter and must be installed in accordance with the requirements
of BS 5440:
Part 1, BS 6644 or IGE/UP/10 as appropriate. The complete flue system must
be designed so as to safely evacuate the products of combustion from the appliance.
The flue pipe should rise for at least 500mm vertically from the draught diverter connection
before any change in direction. Any horizontal runs should include a rise of 60mm per
1000mm run.
A method of disconnection should be included in the flue immediately above the draught
diverter allowing removal for servicing purposes. The flue must be adequately supported and
the draught diverter must not be used to support the flue.
If the flue pipe is run through a cold, unheated area, or outside, it should be of twin wall
construction providing insulation to prevent condensation forming.
IMPORTANT Flue terminal locations must be in accordance with BS5440 part 1, BS6644
and IGE/UP/10, or subject to manufacturer’s guidance.
b. Ventilation
It is important to ensure that an adequate supply of fresh air for combustion and
general plant room ventilation is provided in accordance with BS5440 part 2, BS6644
& IGE/UP/10. The following requirements for natural ventilation direct to outside must
be met:
Alternatively, the ventilation requirement may be met by the provision of mechanically
supplied and mechanically extracted air (interlocked to the appliance to prevent
appliance operation in the event of mechanical system failure) or mechanically
supplied air (interlocked) and natural extract at the rate of: Supply air at 2.8m
3
/h per
kW of net appliance input and a difference between inlet & extract (inlet minus
extract) air at 2m
3
/h per kW of net heat input.
NHREX 18 26 36 60
High level
(free area cm
2
)
44 64 84 120
Low level
(free area cm
2
)
88 128 168 240
Figure 9.1 - Ventilation requirements
c. Tips & Recommendations
➢
The appliance must be connected to the flue system using certified pipes that
resist combustion products, condensates and temperature of at least 135°C.
➢
The flue system should be installed in accordance with regulations and the
manufacturer’s instructions. It must be adequately supported with the ability to
dismantle or remove sections if necessary. This duct diameter must not be
smaller than the appliance connection.
➢
This flue system must be protected from any mechanical shock.
Page 19
10. ELECTRICAL CONNECTION
Wiring external to the appliance must be in accordance with the I.E.E. Wiring
Regulations and any Local Regulations which apply. Wiring must be completed in
heat resistant cable of 1.0mm
2
cross sectional area.
The heater is supplied for connection to a 230volt, 50 Hz, A.C. Single phase. Fuse
rating is a 3 amp.
The method of connection to the mains electricity supply must facilitate complete
electrical isolation to the heater preferably a 3 amp fused double-pole switch with
neon, having a 3mm contact separation in both poles and serving only the heater.
The point of connection to the mains should be readily accessible and adjacent to the
heater.
The appliance is phase-sensitive. It is absolutely essential to connect the mains live
(L) to the live of the appliance, and the mains neutral (N) to the neutral of the
appliance.
Refer to wiring diagram - Figure 10
Note: The manufacturer cannot be held responsible for any damage caused by the lack,
or inadequacy, of the connection of the appliance to an effective grounding system.
FF
Overheat safety
thermostat
Thermostat of
régulation
L
N
Electrode
ionization
Electrode
ignition
Reset button
Flame
indicator
Flue spillage security
Brown
Blue
Black
Black
Neutre
Ground
Phase
Neutre
Ground
Phase
Black
Black
Electronic blo ck
ProTech
Protech
Anode
Ramp safety thermostat
Qte de 1 à 3
T3
Gas valve coil
Thermocouple
Ramp Safety
thermostat
T2
T1
NHREX 26-36-60
NHREX 18
Overheat safety
thermostat
Flue spillage security
Electronic b lo ck
ProTech
Figure 10 – Wiring Diagram
Note - the NHREX 18 has self energising controls and only requires an electrical supply to
support the integral Protech electronic anode system.
A permanent electrical supply is required to ensure that the Protech system is energised and
protecting the tank.
11. INSTALLATION
Before commissioning ensure that the installation is correct:
➢Correct Hydraulic connection
➢Tank under pressure and filled
➢Electrical supply polarity correct
➢Gas soundness
➢Correct installation of flue system
➢Correct installation of condensate tray drain
➢Controls correctly set
a. Initial commissioning
✓ Ensure that the tank is filled with water (very important). Let the air out of the
vent tube (7) and collect the equivalent of a glass of water. Close the vent tube.
Never start the appliance without water in the tank!
✓ Purge any air from the water tank and gas supply.
✓ Electrically power the unit
✓ Open the gas stop valve
WARNING : CHECK THE POLARITY OF THE POWER SUPPLY
During a first commissioning or after prolonged period of shutdown, the purging
of the gas circuit is carried out by several start-up tests.
Legend :
1. Gas valve adjustment
2. Piezo igniter
LIGHT THE PILOT
Open the main gas shut-off valve. (At the first commissioning
or after a prolonged stoppage period, purge the pilot flame
circuits during the ignition sequence to avoid unintentional
ignition)
Figure 11.1 NHREX 18 controls
Page 21
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